Vehicle barrier security systems (“VBS systems”) are commonly used to control passage of vehicles at entry points (“checkpoints”) to buildings, facilities, or other locations. VBS systems are quite common at military installations, airports, government buildings, industrial plants, etc. A VBS system typically comprises a movable mechanical barrier designed to stop an unauthorized automobile, truck, or other vehicle from passing through a checkpoint. Typically, a security guard or an automated mechanism (e.g., card reader) is employed to control movement of the barrier. For VBS systems that are designed to prevent a vehicle from deliberate forced entry, the barrier is typically a massive steel or concrete structure able to withstand a head-on crash attempt. The barrier can comprise a steel bar, pipe, gate, or other suitable structure. Another common arrangement for the barrier comprises a series of relatively short vertical columns, called bollards, that rise from the road about three to four feet high at the checkpoint. Another common structure comprises a metal plate positioned across the road which angles up from the checkpoint. In the lowered position, the metal plate lies flat on the road. In the raised position, the metal plate angles up, about two feet. When the barrier is raised, this is referred to as the “closed” position (because the entry way is closed). When the barrier is lowered, this is referred to as the “open” position. These barrier structures are typically actuated upon command by a guard or an automated system to retract to allow or prohibit passage of a vehicle as appropriate.
The barriers are typically massive and heavy, and thus require a lift system that may include electric motors, hydraulic pumps, gear assemblies, etc., to raise and lower the barrier. These components are typically controlled by a controller comprising a microprocessor control system along with other electronic sensing and switching controls. These components may be housed in a stand-alone utility housing, guardhouse, or sentry station. The control system typically has a manual control in the form of a push switch to close the barrier (i.e., raise up the barrier). Such systems should be reliable, since a malfunction can cause the barrier to remain open (thus allowing unauthorized vehicles to enter) or remain closed (thus preventing authorized vehicles to enter). Other types of malfunctions include the barrier raising/lowering unexpectedly. These types of failures can cause damage or injury. Specifically, if the barrier raises when a vehicle is present at the checkpoint, or the barrier unexpectedly moves during servicing by a technician, then damage to the vehicle or injury to the technician can occur.
It is with respect to these and other considerations that the disclosure herein is presented.